To update this thread, I've been able to unlock:
Win a Multiplayer Game
and just a while ago:
The Orb of Draginol
===
The Orb of Draginol might have been broken earlier, but I can confirm it is working as of Ver 2.4
This is how I unlocked it:
I first researched Cultural Influence so Galactic Challenges would unlock. (I don't believe it has any further restrictions) and then eventually activated and won the Challenge. It comes in three stages.
1] First you have to survey a random number of anomalies. Might be some formula to it, but I wasn't paying close enough attention.
2] Then, after you have surveyed enough anomalies, the game will tell you that found a "pocket universe" and you're given an artifact to store in your Vault which will summon a bunch of Dread Lord ships along with a Dread Lord Shipyard at a spot of your choosing on the map.
Now here's the part which might have been bugged or is new or, well, I dunno since I only came back to GC4 recently.
3] Once you have destroyed all of the Dread Lord ships and shipyard, whichever is the weakest civ in the game will get the Orb of Draginol (technically called a Galactic Achievement) and you have to go to whatever planet it was built on and capture that planet.
Once you capture that planet, an event will (eventually that turn) play and you're given a choice to either begin investigating the Orb, or say you want nothing to do with it. Each one will give you different benefits.
Once you make your choice, the achievement should pop. At least it did for me when I chose the first option to begin investigating it:
FWIW, the Challenge itself, or at least the last stage of it, is somewhat similar to the Artifact Mega Event in GC3 where the weakest civ in the game would get a power boost and you had to go stomp them before they got too big for their britches.
Now the nice thing is, and this might also be what might have caused some problems, is that this is an Orbital Improvement (fitting, no?). And while it can be on any world, you can also see ahead of time just which world it is on by looking at the orbital slots of all of the colonies of the civ that got the Orb, find which one built the Orb and then go grab it:
In fact, as I was just typing now, I wonder if the fact that the Orb can be built on colonies is what might have been the issue. If you haven't gone out of your way to take all of the colonies of the offending civ and then eliminate all of their Core Worlds... Well, since all of the colonies will then turn in inert dead worlds, and that would probably flush the Orb along with it. Not that I tested it to see what happened if I purposefully ignored the world with the Orb and just kicked the Festron in the head and wiped out all of their Core Worlds.
Either way, I can confirm the Orb cheevo is now unlockable.
